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Condensation single-component scheme stability improvements
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@nichollsh
nichollsh committed Jul 19, 2024
1 parent 42a8c07 commit 77ebbbc
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Showing 4 changed files with 83 additions and 60 deletions.
7 changes: 5 additions & 2 deletions src/AGNI.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -336,9 +336,12 @@ module AGNI
target_olr = cfg["planet"]["target_olr"]
end

# Setup atmosphere
@info "Setting up"
# Create atmosphere structure
@debug "Instantiate atmosphere"
atmos = atmosphere.Atmos_t()

# Setup atmosphere
@debug "Setup atmosphere "
return_success = atmosphere.setup!(atmos, ROOT_DIR, output_dir,
spfile_name,
instellation, asf_sf, albedo_b, zenith,
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7 changes: 4 additions & 3 deletions src/atmosphere.jl
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Expand Up @@ -435,7 +435,6 @@ module atmosphere
@error "VMRs provided twice"
return false
end

if isempty(mf_path) && isempty(mf_dict)
@error "VMRs not provided"
return false
Expand Down Expand Up @@ -832,7 +831,8 @@ module atmosphere
end

# Mass (per unit area, kg m-2) and density (kg m-3)
for i in 1:atmos.atm.n_layer
# Loop from top downards
for i in 1:atmos.nlev_c
atmos.layer_mass[i] = (atmos.pl[i+1] - atmos.pl[i])/atmos.layer_grav[i]
atmos.atm.mass[1, i] = atmos.layer_mass[i] # pass to SOCRATES

Expand Down Expand Up @@ -875,7 +875,8 @@ module atmosphere
length=atmos.nlev_l-1))

# Shrink near-surface layers by stretching all layers above
p_mid::Float64 = atmos.pl[end-1]*0.6 + atmos.pl[end-2]*0.4
p_fact::Float64 = 0.6
p_mid::Float64 = atmos.pl[end-1]*p_fact + atmos.pl[end-2]*(1.0-p_fact)
atmos.pl[1:end-2] .= collect(Float64, range( start=atmos.pl[1],
stop=p_mid,
length=atmos.nlev_l-2))
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26 changes: 13 additions & 13 deletions src/energy.jl
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Expand Up @@ -473,14 +473,14 @@ module energy

# Check for spurious shallow convection in condensing regions
# If found, reset convective flux to zero AT THIS LAYER ONLY.
# for i in 2:atmos.nlev_l-1
# if any(atmos.mask_l[i:end])
# if atmos.mask_c[i] && !atmos.mask_c[i-1] && !atmos.mask_c[i+1]
# atmos.mask_c[i] = false
# atmos.flux_cdry[i] = 0.0
# end
# end
# end
for i in 2:atmos.nlev_l-1
if atmos.mask_l[i]
if atmos.mask_c[i] && !atmos.mask_c[i-1] && !atmos.mask_c[i+1]
atmos.mask_c[i] = false
atmos.flux_cdry[i] = 0.0
end
end
end

return nothing
end # end of mlt
Expand Down Expand Up @@ -539,8 +539,8 @@ module energy
end

# relaxation function
atmos.phs_wrk_df[i] = (atmos.gas_vmr[c][i]-qsat) *
atmos.p[i] * atmos.layer_thick[i]/atmos.phs_tau_sgl
atmos.phs_wrk_df[i] = (atmos.gas_vmr[c][i]-qsat)* atmos.layer_thick[i]*
(atmos.pl[i+1]-atmos.pl[i])/ atmos.phs_tau_sgl

# flag layer as set by saturation
if atmos.phs_wrk_df[i] > 1.0e-10
Expand Down Expand Up @@ -572,16 +572,16 @@ module energy
E_accum = sum(atmos.phs_wrk_df[1:i_dry_top])

# evaporative flux in dry region
for i in i_dry_top:atmos.nlev_c
for i in i_dry_top+1:atmos.nlev_c

if E_accum < 1.0e-2
if E_accum < 0.1
# dissipate all of the flux
atmos.phs_wrk_df[i] = -E_accum
E_accum = 0.0
break
else
# dissipate some fraction of the accumuated flux
atmos.phs_wrk_df[i] = -0.9*E_accum
atmos.phs_wrk_df[i] = -0.8*E_accum
E_accum += atmos.phs_wrk_df[i]
end

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103 changes: 61 additions & 42 deletions src/solver.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,7 @@ module solver
- `modplot::Int` iteration frequency at which to make plots
- `save_frames::Bool` save plotting frames
- `modprint::Int` iteration frequency at which to print info
- `plot_jacobian::Bool` plot jacobian too?
- `conv_atol::Float64` convergence: absolute tolerance on per-level flux deviation [W m-2]
- `conv_rtol::Float64` convergence: relative tolerance on per-level flux deviation [dimensionless]
Expand All @@ -106,10 +107,10 @@ module solver
max_steps::Int=2000, max_runtime::Float64=600.0,
fdw::Float64=3.0e-5, fdc::Bool=true, fdo::Int=2,
method::Int=1,
linesearch::Bool=true, easy_start::Bool=true,
linesearch::Bool=true, easy_start::Bool=false,
detect_plateau::Bool=true, perturb_all::Bool=false,
modplot::Int=1, save_frames::Bool=true,
modprint::Int=1,
modprint::Int=1, plot_jacobian::Bool=true,
conv_atol::Float64=1.0e-2, conv_rtol::Float64=1.0e-3
)::Bool

Expand All @@ -135,20 +136,21 @@ module solver
# --------------------
# Execution parameters
# --------------------
# convection
# easy_start
easy_incr::Float64 = 3.0 # Factor by which to increase easy_sf at each step
easy_sf::Float64 = 1.0e-5 # Convective & phase change flux scale factor
easy_sf::Float64 = 2.0e-4 # Convective & phase change flux scale factor
easy_trig::Float64 = 0.5 # Increase sf when cost*easy_trig satisfies convergence

# finite difference
fdr::Float64 = 0.01 # Use forward difference if cost ratio is below this value
perturb_conv::Float64 = 0.02 # Require full Jacobian update when c_cur*peturb_conv satisfies convergence
perturb_trig::Float64 = 0.1 # Require full Jacobian update when cost*peturb_trig satisfies convergence
perturb_crit::Float64 = 0.1 # Require Jacobian update at level i when r_i>perturb_crit
perturb_mod::Int = 10 # Do full jacobian at least this frequently

# linesearch
ls_method::Int = 1 # linesearch algorithm (1: golden, 2: backtracking)
ls_tau::Float64 = 0.5 # backtracking downscale size
ls_increase::Float64 = 1.5 # factor by which cost can increase
ls_increase::Float64 = 2.0 # factor by which cost can increase
ls_max_steps::Int = 15 # maximum steps
ls_min_scale::Float64 = 4.0e-5 # minimum scale

Expand Down Expand Up @@ -195,6 +197,7 @@ module solver
runtime::Float64 = 0.0 # Model runtime [s]
fc_retcode::Int = 0 # Fastchem return code
step_ok::Bool = true # Current step was fine
easy_step::Bool = false # easy_start sf increased in this step
plateau_i::Int = 0 # Number of iterations for which step was small

# statistics
Expand Down Expand Up @@ -233,10 +236,10 @@ module solver
fill!(atmos.mask_c, false)
fill!(atmos.mask_l, false)

# Set temperatures
# Set new temperatures
_set_tmps!(x)

# Calculate layer properties if required and haven't already
# Calculate layer properties
atmosphere.calc_layer_props!(atmos)

# Handle rainout (but not energy release)
Expand Down Expand Up @@ -509,22 +512,26 @@ module solver
step_ok = step_ok && atmosphere.calc_layer_props!(atmos)

# Check convective modulation
easy_step = false
if easy_start
# We are modulating
stepflags *= "M"

# Check if sf needs to be increased
if c_cur < max(100.0*conv_rtol, 10.0)
if c_cur*easy_trig < conv_atol + conv_rtol * c_max
if easy_sf < 1.0
# increase sf => reduce modulation by easy_incr
stepflags *= "r"
easy_sf = min(1.0, easy_sf*easy_incr)
easy_step = true
@debug "easy_sf = $easy_sf"

# done modulating
if easy_sf > 0.99
easy_start = false
end
else
easy_sf = 1.0
end
end

Expand All @@ -539,8 +546,8 @@ module solver

# Determine which parts of the Jacobian matrix need to be updated
@debug " jacobian"
if (step == 1) || perturb_all ||
(c_cur*perturb_conv < conv_atol + conv_rtol * c_max) ||
if (step == 1) || perturb_all || easy_step ||
(c_cur*perturb_trig < conv_atol + conv_rtol * c_max) ||
mod(step,perturb_mod)==0
# Update whole matrix if:
# on first step, was requested, or near global convergence
Expand Down Expand Up @@ -613,9 +620,9 @@ module solver
stepflags *= "Lm-"
end

# Extrapolate step if on plateau
# this acts to give the solver a 'nudge' in (hopefully) the
# right direction. Otherwise, this perturbation can still help.
# Extrapolate step if on plateau.
# This acts to give the solver a 'nudge' in (hopefully) the right direction.
# Otherwise, this perturbation can still help.
if plateau_i > plateau_n
x_dif[:] .*= plateau_s
plateau_i = 0
Expand All @@ -627,55 +634,65 @@ module solver

# Linesearch
# https://people.maths.ox.ac.uk/hauser/hauser_lecture2.pdf
if linesearch #&& (step > 1)
if linesearch
@debug " linesearch"

# Reset
stepflags *= "Ls-"
ls_alpha = 1.0
ls_cost = 1.0e99 # big number

# Internal function minimised by GS search
# Internal function minimised by linesearch method
function _ls_func(scale::Float64)::Float64
x_cur[:] .= x_old[:] .+ scale .* x_dif[:]
_fev!(x_cur,r_tst)
return _cost(r_tst)
end

if ls_method == 1
# Use golden-section minimisation to find best scale
ls_alpha = gs_search(_ls_func, ls_min_scale, ls_alpha,
1.0e-9, ls_min_scale, ls_max_steps)

elseif ls_method == 2
# Use backtracking line search to find best scale
for il in 1:ls_max_steps
ls_cost = _ls_func(ls_alpha)
if ls_cost <= c_cur*ls_increase
# this scale is good enough
break
else
# scale is not good - try shrinking it further
# Do we need to do linesearch?
# A small amount of cost increase is allowed.
# Get the cost if we used the full step size.
ls_cost = _ls_func(ls_alpha)
if ls_cost > c_cur*ls_increase

# Yes, we do need to do linesearch...
stepflags *= "Ls-"

if ls_method == 1
# Use golden-section search method
ls_alpha = gs_search(_ls_func, ls_min_scale, ls_alpha,
1.0e-9, ls_min_scale, ls_max_steps)

elseif ls_method == 2
# Use backtracking method

for il in 1:ls_max_steps
# try shrinking it further
ls_alpha *= ls_tau

if ls_alpha < ls_min_scale
# scale too small!
ls_alpha = ls_min_scale
break
end

ls_cost = _ls_func(ls_alpha)
if ls_cost <= c_cur*ls_increase
# this scale is good enough
break
end
end
end

else
@error "Invalid linesearch algorithm $ls_method"
code = 99
break
else
@error "Invalid linesearch algorithm $ls_method"
code = 99
break
end

# Apply best scale from linesearch
ls_alpha = max(ls_alpha, ls_min_scale)
x_dif[:] .*= ls_alpha
end

ls_alpha = max(ls_alpha, ls_min_scale)

# Apply best scale from linesearch
x_dif[:] .*= ls_alpha

end # end linesearch

# Take the step
Expand Down Expand Up @@ -709,7 +726,9 @@ module solver
# Plot
if (modplot > 0) && (mod(step, modplot) == 0)
plot_step()
# plotting.jacobian(b, path_jac, perturb=perturb)
if plot_jacobian
plotting.jacobian(b, path_jac, perturb=perturb)
end
end

# Inform user
Expand Down

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